Answer:
Magnetic field, B = 0.0045 T
Step-by-step explanation:
It is given that,
Speed of the proton,

Acceleration of the proton,

Charge on proton,

The magnetic force is balanced by the force due to the acceleration of the proton as :



B = 0.0045 T
So, the magnitude of magnetic field on the proton is 0.0045 T. Hence, this is the required solution.